A362353 - OEIS

%I #17 Aug 02 2023 13:49:21

%S 1,-3,4,9,-32,25,-27,192,-375,216,81,-1024,3750,-5184,2401,-243,5120,

%T -31250,77760,-84035,32768,729,-24576,234375,-933120,1764735,-1572864,

%U 531441,-2187,114688,-1640625,9797760,-28824005,44040192,-33480783,10000000,6561,-524288,10937500,-94058496,403536070,-939524096,1205308188,-800000000,214358881

%N Triangle read by rows: T(n,k) = (-1)^(n-k)*binomial(n, k)*(k+3)^n, for n >= 0, and k = 0,1, ..., n. Coefficients of certain Sidi polynomials.

%C This is the member N = 2 of a family of signed triangles with row sums n! = A000142(n): T(N; n, k) = (-1)^(n-k)*binomial(n, k)*(k + N + 1)^n, for integer N, n >= 0 and k = 0, 1, ..., n. The row polynomials PS(N; n, z) = Sum_{k=0..n} T(N; n, k)*z^k = ((-1)^n/z^N)*D_{n,N+1,n}(z) in [Sidi 1980].

%C For N = -1, 0 and 1 see A258773(n, k), A075513(n+1, k) and (-1)^(n-k) * A154715(n, k), respectively.

%C The column sequences, for k = 0, 1, ..., 6 and n >= k, are A141413(n+2), (-1)^(n+1)*A018215(n) = 4*(-1)^(n+1)*A002697(n), 5^2*(-1)^n*A081135(n), (-1)^(n+1)*A128964(n-1) = 6^3*(-1)^(n+1)*A081144(n), 7^4*(-1)^n*A139641(n-4), 2^15*(-1)^(n+1)*A173155(n-5), 3^12*(-1)^n*A173191(n-6), respectively.

%C The e.g.f. of the triangle (see below) needs the exponential convolution (LambertW(-z)/(-z))^2 = Sum_{n>=0} c(2; n)*z^n/n!, where c(2; n) = Sum_{m=0..n} |A137352(n+1, m)|*2^m = A007334(n+2).

%C The row sums give n! = A000142(n).

%H Paolo Xausa, <a href="/A362353/b362353.txt">Table of n, a(n) for n = 0..5049</a> (rows 0..100 of the triangle, flattened)

%H Wolfdieter Lang, <a href="/A075513/a075513.pdf">On a Certain Family of Sidi Polynomials</a>, May 2023.

%H Avram Sidi, <a href="https://doi.org/10.1090/S0025-5718-1980-0572861-2">Numerical Quadrature and Nonlinear Sequence Transformations; Unified Rules for Efficient Computation of Integrals with Algebraic and Logarithmic Endpoint Singularities</a>, Math. Comp., 35 (1980), 851-874.

%F T(n, k) = (-1)^(n-k)*binomial(n, k)*(k + 3)^n, for n >= 0, k = 0, 1, ..., n.

%F O.g.f. of column k: (x*(k + 3))^k/(1 - (k + 3)*x)^(k+1), for k >= 0.

%F E.g.f. of column k: exp(-(k + 3)*x)*((k + 3)*x)^k/k!, for k >= 0.

%F E.g.f. of the triangle, that is, the e.g.f. of its row polynomials {PS(2;n,y)}_{n>=0}): ES(2;y,x) = exp(-3*x)*(1/3)*(d/dz)(W(-z)/(-z))^2, after replacing z by x*y*exp(-x), where W is the Lambert W-function for the principal branch. This becomes ES(2;y,x) = exp(-3*x)*exp(3*(-W(-z)))/(1 - (-W(-z)), with z = x*y*exp(-x).

%e The triangle T begins:

%e n\k    0       1        2         3         4          5          6         7

%e 0:     1

%e 1:    -3       4

%e 2:     9     -32       25

%e 3:   -27     192     -375       216

%e 4:    81   -1024     3750     -5184      2401

%e 5:  -243    5120   -31250     77760    -84035      32768

%e 6:   729  -24576   234375   -933120   1764735   -1572864     531441

%e 7: -2187  114688 -1640625   9797760 -28824005   44040192  -33480783  10000000

%e ...

%e n = 8:  6561 -524288 10937500 -94058496 403536070 -939524096 1205308188 -800000000 2143588,

%e n = 9: -19683 2359296 -70312500 846526464 -5084554482 16911433728 -32543321076 36000000000 -21221529219 5159780352.

%t A362353row[n_]:=Table[(-1)^(n-k)Binomial[n,k](k+3)^n,{k,0,n}];Array[A362353row,10,0] (* _Paolo Xausa_, Jul 30 2023 *)

%Y Cf. A000142 (row sums), A075513, A154715, A258773.

%Y Columns k = 0..6 involve (see above): A002697, A007334, A018215, A081135, A081144, A128964, A137352, A139641, A141413, A173155, A173191.

%K sign,tabl,easy

%O 0,2

%A _Harlan J. Brothers_ and _Wolfdieter Lang_, Apr 27 2023

%E a(41)-a(44) from _Paolo Xausa_, Jul 31 2023